Fluid control element for biopsy apparatus

ABSTRACT

A fluid control element having a flexible member that is adapted for selective deformation when an element inserted therein. The flexible member includes at least one incision or opening that defines at least one cusp that selectively opens when the element is inserted therein. The incision or opening is biased into a normally and substantially closed position such that fluids are substantially prevented from flowing through the fluid control element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation in Part of U.S. application Ser. No.10/958,026 filed on Oct. 4, 2004 which is a Continuation of U.S.application Ser. No. 10/848,278 filed on May 18, 2004 which is aDivisional of U.S. application Ser. No. 09/707,022 filed Nov. 6, 2000,now U.S. Pat. No. 6,758,824. This application is also related toapplication Ser. No. 10/639,569 filed Aug. 12, 2003 which is aDivisional of application Ser. No. 09/864,031 filed on May 23, 2001, nowU.S. Pat. No. 6,638,235, which is a Continuation-in-Part of applicationSer. No. 09/707,022 filed Nov. 6, 2000, now U.S. Pat. No. 6,758,824.

FIELD OF THE INVENTION

This invention generally relates to biopsy instruments and methods fortaking a biopsy. More specifically, this invention relates to a fluidiccontrol device to be used with a biopsy device.

BACKGROUND OF THE INVENTION

In the diagnosis and treatment of breast cancer, it is often necessaryto remove multiple tissue samples from a suspicious mass. The suspiciousmass is typically discovered during a preliminary examination involvingvisual examination, palpitation, X-ray, MRI, ultrasound imaging or otherdetection means. When this preliminary examination reveals a suspiciousmass, the mass must be evaluated by taking a biopsy in order todetermine whether the mass is malignant or benign. Early diagnosis ofbreast cancer, as well as other forms of cancer, can prevent the spreadof cancerous cells to other parts of the body and ultimately preventfatal results.

A biopsy can be performed by either an open procedure or a percutaneousmethod. The open surgical biopsy procedure first requires localizationof the lesion by insertion of a wire loop, while using visualizationtechnique, such as X-ray or ultrasound. Next, the patient is taken to asurgical room where a large incision is made in the breast, and thetissue surrounding the wire loop is removed. This procedure causessignificant trauma to the breast tissue, often leaving disfiguringresults and requiring considerable recovery time for the patient. Thisis often a deterrent to patients receiving the medical care theyrequire. The open technique, as compared to the percutaneous method,presents increased risk of infection and bleeding at the sample site.Due to these disadvantages, percutaneous methods are often preferred.

Percutaneous biopsies have been performed using either Fine NeedleAspiration or core biopsy in conjunction with real-time visualizationtechniques, such as ultrasound or mammography (X-ray). Fine NeedleAspiration involves the removal of a small number of cells using anaspiration needle. A smear of the cells is then analyzed using cytologytechniques. Although Fine Needle Aspiration is less intrusive, only asmall amount of cells are available for analysis. In addition, thismethod does not provide for a pathological assessment of the tissue,which can provide a more complete assessment of the stage of the cancer,if found. In contrast, in core biopsy a larger fragment of tissue can beremoved without destroying the structure of the tissue. Consequently,core biopsy samples can be analyzed using a more comprehensive histologytechnique, which indicates the stage of the cancer. In the case of smalllesions, the entire mass may be removed using the core biopsy method.For these reasons core biopsy is preferred, and there has been a trendtowards the core biopsy method, so that a more detailed picture can beconstructed by pathology of the disease's progress and type.

The first core biopsy devices were of the spring advanced, “Tru-Cut”style consisting of a hollow tube with a sharpened edge that wasinserted into the breast to obtain a plug of tissue. This devicepresented several disadvantages. First, the device would sometimes failto remove a sample, therefore, requiring additional insertions. This wasgenerally due to tissue failing to prolapse into the sampling notch.Secondly, the device had to be inserted and withdrawn to obtain eachsample, therefore, requiring several insertions in order to acquiresufficient tissue for pathology.

The biopsy apparatus disclosed in U.S. Pat. No. 5,526,822 to Burbank, etal was designed in an attempt to solve many of these disadvantages. TheBurbank apparatus is a biopsy device that requires only a singleinsertion into the biopsy site to remove multiple tissue samples. Thedevice incorporates a tube within a tube design that includes an outerpiercing needle having a sharpened distal end for piercing the tissue.The outer needle has a lateral opening forming a tissue receiving port.The device has an inner cannula slidingly disposed within the outercannula, and which serves to cut tissue that has prolapsed into thetissue receiving port. Additionally, a vacuum is used to draw the tissueinto the tissue receiving port. Vacuum assisted core biopsy devices,such as the Burbank apparatus, are available in handheld (for use withultrasound) and stereotactic (for use with X-ray) versions. Stereotacticdevices are mounted to a stereotactic unit that locates the lesion andpositions the needle for insertion. In preparation for a biopsy using astereotactic device, the patient lies face down on a table, and thebreast protrudes from an opening in the table. The breast is thencompressed and immobilized by two mammography plates. The mammographyplates create images that are communicated in real-time to thestereotactic unit. The stereotactic unit then signals the biopsy deviceand positions the device for insertion into the lesion by the operator.

In contrast, when using the handheld model, the breast is notimmobilized. Rather the patient lies on her back and the doctor uses anultrasound device to locate the lesion. The doctor must thensimultaneously operate the handheld biopsy device and the ultrasounddevice.

Although the Burbank device presents an advancement in the field ofbiopsy devices, several disadvantages remain and further improvementsare needed. For example, the inner cutter must be advanced manually,meaning the surgeon manually moves the cutter back and forth by lateralmovement of a knob mounted on the outside of the instrument or by one ofthe three pedals at the footswitch. Also, the vacuum source that drawsthe tissue into the receiving port is typically supplied via a vacuumchamber attached to the outer cannula. The vacuum chamber defines atleast one, usually multiple, communicating holes between the chamber andthe outer cannula. These small holes often become clogged with blood andbodily fluids. The fluids occlude the holes and prevent the aspirationfrom drawing the tissue into the receiving port. This ultimatelyprevents a core from being obtained, a condition called a “dry tap.”

In addition, many of the components of the current biopsy devices arereusable, such as the driver portions, which control the outer and innerneedles. This poses several notable disadvantages. First, the reusableportion must be cleaned and/or sterilized. This increases the timenecessary to wrap up the procedure, which ultimately affects the cost ofthe procedure. In addition, the required clean-up and/or sterilizationof reusable parts increases the staffs' potential exposure to bodytissues and fluids. Finally, the reusable handle is heavy, large andcumbersome for handheld use.

A further disadvantage is that current biopsy devices comprise an opensystem where the tissue discharge port is simply an open area of thedevice. A surgical assistant must remove the tissue from the opencompartment using forceps and place the tissue on a sample plate. Thisritual must be followed for every sample and, therefore, multipleoperators are required. In addition, the open system increases theexposure to potentially infectious materials, and requires increasedhandling of the sample. As a practical matter, the open system alsosubstantially increases the clean-up time and exposure, because asignificant amount of blood and bodily fluid leaks from the device ontothe floor and underlying equipment.

Additionally, when using the current biopsy devices, physicians haveencountered significant difficulties severing the tissue. For instance,the inner cutter often fails to completely sever the tissue. When theinner cutting needle is withdrawn, no tissue sample is present (drytap), and therefore, reinsertion is required. In the case of the Burbankapparatus, the failure to completely sever the tissue after the firstadvancement of the inner cutter results in a necessary secondadvancement of the inner cutter. In this event, the procedure isprolonged, which is significant because the amount of trauma to thetissue and, ultimately, to the patient is greatly affected by the lengthof the procedure. Therefore, it is in the patient's best interest tominimize the length of the procedure by making each and every attempt atcutting the tissue a successful and complete cut.

Additionally, when using the “tube within a tube” type biopsy device,the inner cutter can lift up into the tissue receiving opening duringcutting. This lifting causes the inner cutter to catch on the edge ofthe tissue receiving opening, which ultimately results in an incompletecut and dulling of the blade, rendering the blade useless.

Also, prior devices often produce small tissue samples. As the innercutter advances, the cutting edge not only starts to sever the tissue,it also pushes the tissue in front of the cutter. This results in atissue sample that is smaller than the amount of tissue drawn into thetissue receiving opening.

An additional disadvantage of the prior devices is presented by thecomplexity of the three-pedal footswitch. Prior devices utilized athree-pedal footswitch; one pedal for advancing the inner cannula,another pedal for retracting the inner cannula, and a third pedal forturning on the aspiration. Operation of the three pedals is difficultand awkward.

These disadvantages become even more significant when using the handheldbiopsy device. For instance, the physician must operate the biopsydevice and the ultrasound probe simultaneously making it particularlydifficult to manually advance the inner cutter. In addition, when anassistant is required to remove each sample from the open dischargeport, use of the handheld device becomes even more awkward. Due to thesedisadvantages, many physicians have declined to use the handheld model.

This is unfortunate because, some lesions that can signify the possiblepresence of cancer cannot be seen using the stereotactic unit. In thesecases, the doctor must resort to either the handheld device or opensurgical biopsy. Due to the difficulties associated with the handhelddevice, doctors often choose the open surgical biopsy, which isparticularly unfortunate because a majority of the lesions that cannotbe seen using the sterotactic unit turn out to be benign. This meansthat the patient has unnecessarily endured a significant amount of painand discomfort; not to mention extended recovery time and disfiguringresults. In addition, the patient has likely incurred a greaterfinancial expense because the open surgical technique is more difficult,time consuming and costly, especially for those patients without healthinsurance.

The disadvantages of the open surgical technique coupled with the oddsthat the lesion is benign present a disincentive for the patient toconsent to the biopsy. The added discomfort alone is enough to causemany patients to take the risk that the lesion is benign. The acceptanceof this risk can prove to be fatal for the minority of cases where thelesion is malignant.

Finally, current vacuum assisted biopsy devices are not capable of beingused in conjunction with MRI. This is due to the fact that many of thecomponents are made of magnetic components that interfere with theoperation of the MRI. It would be desirable to perform biopsies inconjunction with MRI because it currently is the only non-invasivevisualization modality capable of defining the margins of the tumor.

BRIEF SUMMARY

In one embodiment of the present invention, a tissue removal device isprovided that includes a cutting element. The cutting element includesan outer cannula defining a tissue-receiving opening and an innercannula concentrically disposed within the outer cannula. In accordancewith one aspect of the invention, the outer cannula may further includeat least one fluid control element for controlling the flow of fluidsthrough the tissue removal device.

The inner cannula defines an inner lumen that extends the length of theinner cannula, and which provides an avenue for aspiration. In oneembodiment, the inner cannula may also include a fluid control element.

Vacuum is applied to the inner lumen through an aspiration tube. Theaspiration tube may communicate with a collection trap that is mountedto the handpiece. Vacuum draws the sample into the tissue-receivingopening and after the tissue is cut, draws the tissue through the innercannula to the collection trap. In one embodiment, the collection trapmay have one or more fluid control elements associated with it forcontrolling the flow of fluids from the collection trap to theaspiration tube. In another embodiment, the aspiration tube may also beprovided with a fluid control element.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of a tissue biopsy apparatus inaccordance with one embodiment of the present invention.

FIG. 2 is a top elevational view of the tissue biopsy apparatus shown inFIG. 1.

FIGS. 3A and 3B are side cross-sectional views of the tissue biopsyapparatus depicted in FIGS. 1 and 2, with the tissue cutting innercannula shown in its retracted and extended positions, respectively.

FIGS. 4A and 4B are enlarged side views of the inner cannula having afluid control element disposed therein.

FIGS. 4C and 4D are enlarged front views of alternative embodiments ofthe fluid control element of FIGS. 4A and 4B.

FIG. 4E is an enlarged side view of a fluid control element having atapered and elongated profile.

FIGS. 4F and 4G are enlarged front views of alternative embodiments ofthe fluid control element of FIG. E.

FIGS. 4H and 4I are enlarged views of an outer cannula hub member shownin FIGS. 3A and 3B having a fluid control element, taken along lines4-4.

FIG. 4J is a perspective view of the outer cannula hub member shown inFIGS. 3A and 3B having the inner cannula disposed within the outercannula.

FIG. 4K is a partially exploded cross-sectional view of a collectioncanister having an embodiment of a fluid control element therein.

FIG. 4L is a top plan view of the fluid control element of FIG. 4K.

FIG. 4M is a cross-sectional view of an embodiment of a fluid controlelement in an uncompressed and closed position as shown in FIG. 3A.

FIG. 4N is an enlarged front view of an embodiment of the fluid controlelement of FIG. 4M.

FIG. 4P is a cross-sectional view of fluid control element of FIG. 4M ina compressed and open position as shown in FIG. 3B.

FIG. 4Q is an enlarged front view of an embodiment of the fluid controlelement of FIG. 4P.

FIG. 5 is a perspective view of a cover for the tissue biopsy apparatusas shown FIG. 1.

FIG. 6 is an enlarged side cross-sectional view of the operating end ofthe tissue biopsy apparatus depicted in FIGS. 1 and 2.

FIG. 7 is a side partial cross-sectional view of working end of a tissuebiopsy apparatus in accordance with an alternative embodiment.

FIG. 8 is an end cross-sectional view of the apparatus depicted in FIG.7, taken along lines 8-8.

FIG. 9 is an end cross-sectional view similar to FIG. 8 showing amodified configuration for a stiffening member.

FIG. 9A is an end cross-sectional view similar to FIG. 8 showing amodified configuration for another stiffening member.

FIG. 10 is an enlarged side cross-sectional view of a fluid introductionport at the hub connecting the outer cannula to the handpiece for atissue biopsy apparatus as depicted in FIG. 1.

FIG. 11 is a schematic drawing of the hydraulic control system for theoperation of the tissue biopsy apparatus shown in FIG. 1.

FIG. 12 is a schematic drawing of an electric motor control systemaccording to another embodiment of the invention.

FIG. 13 is an enlarged perspective view of an embodiment of a fluidcontrol element taken from circle 13 in FIG. 3B.

FIG. 14 is an enlarged perspective view of the fluid control element ofFIG. 13 taken from a second end.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended. The invention includes any alterationsand further modifications in the illustrated devices and describedmethods and further applications of the principles of the inventionwhich would normally occur to one skilled in the art to which theinvention relates.

A tissue biopsy apparatus 10 in accordance with one embodiment of thepresent invention is shown in FIGS. 1-6. The apparatus 10 includes acutting element 11 mounted to a handpiece 12. The cutting element 11 issized for introduction into a human body. Thus, the cutting element 11and the overall biopsy apparatus 10 are configured for ease of use inthis surgical environment. In the illustrated embodiment, the biopsyapparatus 10 is configured as a hand-held device. However, the sameinventive principles may be employed in a tissue biopsy apparatus thatis used stereotatically in which the apparatus is mounted on a supportfixture that is used to position the cutting element 11 relative to thetissue to be sampled. Nevertheless, for the purposes of understandingthe present invention, the tissue biopsy apparatus will be described asa hand-held device.

The cutting element 11 is configured as a “tube-within-a-tube” cuttingdevice. More specifically, the cutting element 11 includes an outercannula 15 terminating in a tip 16. Preferably, the tip is a trocar tipthat can be used to penetrate the patient's skin. Alternatively, the tip16 can simply operate as a closure for the open end of the cannula 15.In this instance, a separate introducer would be required.

The cutting element 11 further includes an inner cannula 17 that fitsconcentrically within the outer lumen 27 (FIG. 6) of the outer cannula15. In one embodiment, both a rotary motor 20 (FIG. 1) and areciprocating motor 22 drive the inner cannula 17. Both motors aresupported within the handpiece 12. Again, in accordance with oneembodiment the rotary motor 20 and reciprocating motor 22 are configuredfor simultaneous operation to translate the inner cannula 17 axiallywithin the outer cannula 15, while rotating the inner cannula 17 aboutits longitudinal axis.

One specific configuration of the working end of the cutting element 11is depicted in FIG. 6. The outer cannula 15 defines a tissue-receivingopening 25, which communicates with the outer lumen 27. A pair ofopposite longitudinal edges 26 (FIGS. 1 and 2) define thetissue-receiving opening 25. The outer cannula 15 is open at its distalend 28 with the trocar tip 16 engaged therein. Preferably, the trocartip 16 forms an engagement hub 30 that fits tightly within the distalend 28 of the outer cannula 15. The hub 30 can be secured by welding,press-fit, adhesive or other means suitable for a surgical biopsyinstrument.

The working end of the cutting element 11 may further include a cuttingboard 31 that is at least snugly disposed within the outer lumen 27 atthe distal end 28 of the outer cannula 15. In one embodiment, thecutting board 31 is in direct contact with the engagement hub 30 of thetrocar tip 16. The cutting board 31 can be permanently affixed withinthe outer cannula 15 and/or against the engagement hub 30 of the trocartip.

The inner cannula 17 defines an inner lumen 34 that is hollow along theentire length of the cannula to provide for aspiration of the biopsysample. The inner cannula 17 terminates in a cutting edge 35. Preferablythe cutting edge 35 is formed by an inwardly beveled surface 36 toprovide a razor-sharp edge. The inwardly beveled surface helps eliminatethe risk of catching the edge 35 on the tissue-receiving opening 25 ofthe outer cannula. In addition, the beveled surface 36 helps avoidpinching the biopsy material between the inner and outer cannulas duringa cutting stroke.

In one embodiment, both the outer cannula 15 and the inner cannula 17are formed of a surgical grade metal. Most preferably, the two cannulaeare formed of stainless steel. In the case of an MRI compatible device,the cannulae can be formed of Inconel™, Titanium or other materials withsimilar magnetic characteristics. Likewise, the trocar tip 16 is mostpreferably formed of stainless steel honed to a sharp tip. The trocartip 16 can be suitably bounded to the outer cannula 15, such as bywelding or the use of an appropriate adhesive.

The cutting board 31 is formed of a material that is configured toreduce the friction between the cutting edge 35 of the inner cannula 17and the cutting board 31. The cutting edge 35 necessarily bears againstthe cutting board 31 when the inner cannula 17 is at the end of itsstroke while severing a tissue sample. Since the inner cannula is alsorotating, the cutting edge necessarily bears directly against thecutting board 31, particularly after the tissue sample has been cleanlysevered. In prior devices, the impact-cutting surface has been formed ofthe same material as the cutting element. This leads to significant wearor erosion of the cutting edge. When numerous cutting cycles are to beperformed, the constant wear on the cutting edge eventually renders itincapable of cleanly severing a tissue sample.

Thus, the present invention contemplates forming the cutting board 31 ofa material that reduces this frictional wear. In one embodiment, thecutting board 31 is formed of a material that is mechanically softerthan the material of the cutting edge 35. However, the cutting board 31is typically not so soft that the cutting edge 35 forms a pronouncedcircular groove in the cutting board, which significantly reduces thecutting efficiency of the inner cannula. In a most preferred embodimentof the invention, the cutting board 31 is formed of a plastic material,such as polycarbonate, ABS or DELRIN®.

Returning again to FIGS. 1, 2, and 3A-3B, the rotary motor 20 includes amotor housing 39 that is sized to reciprocate within the handpiece 12.The housing 39 defines a pilot port 40 that is connected to thehydraulic control system 150 (see FIG. 11) by appropriate tubing. Themotor 20 can be a number of hydraulically powered rotating components.Most preferably, the motor 20 is an air motor driven by pressured air.Thus, the motor 20 includes a vaned rotor 42 that is mounted on a hollowtubular axle 43 extending through the motor housing 39. The axle 43 issupported on bearings 44 at opposite ends of the housing so that therotor 42 freely rotates within the motor housing 39 under pneumaticpressure.

In the illustrated embodiment, tubular axle 43 is connected to theproximal end 37 of the inner cannula 17 by way of a coupler 46. The endsof the two tubes are mounted within the coupler 46 and held in place bycorresponding set screws 47. In one embodiment, the coupler 46 is formedof a plastic material that provides a generally airtight seal around thejoint between the inner cannula 17 and the tubular axle 43. It isimportant that the coupler 46 provide a solid connection of the innercannula 17 to the rotating components of the motor 20 so that the innercannula 17 does not experience any torrential slip during the cuttingoperation.

Since the inner cannula 17 provides an avenue for aspiration of thebiopsy sample, the invention further contemplates an aspiration tube 50that mates with the tubular axle 43. (FIG. 3A) Thus, the tissueaspiration path from the working end of the cutting element 11 is alongthe inner lumen 34 of the inner cannula 17, through the tubular axle 43of the rotary motor 20, and through the aspiration tube 50 to a tissuecollection location in the form of a collection trap 55. To maintain thevacuum or aspiration pressure within this aspiration path, theaspiration tube 50 must be fluidly sealed against the tubular axial 43.Thus, the motor housing 39 defines a mounting hub 51 into which theaspiration tube 50 is engaged. The position of the aspiration tube 50 isfixed by way of a setscrew 52 passing through the mounting hub 51. Incontrast to the joint between the inner cannula 17 and the tubular axial43, the joint between the aspiration tube 50 and the tubular axial 43allows relative rotation between the two components. The tubular axle43, of course, rotates with the rotor 42. However, the aspiration tube50 need not rotate for use with the biopsy apparatus. The mounting hub51 can include an arrangement of seal rings (not shown) at the jointbetween the aspiration tube 50 and the tubular axle 43 to further sealthe aspiration system.

In accordance with one aspect of the present invention, disposed withinthe inner cannula 17 is a fluid control element 78 as shown in FIGS. 4Aand 4B. Fluid control element 78 enables control of bodily fluidsthroughout the inner cannula 17 thereby substantially reducing theamount of leakage from the biopsy apparatus. The fluid control element78 may be constructed of a flexible, yet durable material. Accordingly,in one embodiment, fluid control element 78 is constructed of arubberized material. It is recognized however, that fluid controlelement 78 may be constructed of any other suitable selectivelydeformable material capable of controlling the flow of fluids throughinner cannula 17. Additionally, fluid control element 78 has a shape anddiameter that is complementary with the shape and diameter of innerlumen 34. (FIG. 6) Accordingly, when disposed within the inner cannula17, a secure frictional engagement exists between fluid control element78 and inner cannula 17.

In one embodiment, fluid control element 78 may be secured within theinner cannula 17 by the use of an adhesive. In other embodiments, fluidcontrol element 78 may be secured within inner cannula 17 by forming anotch or several notches 17 a within the inner cannula 17. (FIG. 4A)FIG. 4B illustrates yet another embodiment for securing fluid controlelement 78, wherein projections 82 extend inwardly from inner cannula17. In yet another alternative embodiment, fluid control element 78 mayhave a disk shape that is press-fit within the inner cannula 17. It isrecognized that the foregoing embodiments of securing fluid controlelement 78 are examples only and other methods of securing fluid controlelement 78 are contemplated by the present invention.

Referring to FIGS. 4C and 4D, enlarged front views of fluid controlelement 78 are illustrated. As shown, fluid control element 78 has anincision 78 a therein. Incision 78 a enables a controlled flow of fluidsthrough the fluid control element 78 by functioning as a control valvewithin inner cannula 17. In some embodiments, incision 78 a formsmultiple cusps 78 b in fluid control element 78 that are normallyclosed. As illustrated in FIG. 4C, incision 78 a forms four quadrantshaving four cusps 78 b. In an alternative embodiment shown in FIG. 4D, atricuspid fluid control element 78 is formed by incision 78 a, havingthree cusps 78 b. It is contemplated by the present invention thatincision 78 a may have a variety of patterns and is not limited to theforegoing embodiments. The specific pattern of incisions 78 a isdependent upon the design and functional requirements of the biopsyapparatus. In operation, when an element of the biopsy device 10 isinserted into incision 78 a, the fluid control element 78 opens, butonly wide enough to permit the passage of the biopsy device element.Thus, the fluid control element 78 substantially seals around the biopsydevice element.

In another embodiment, to provide fluid control, aspiration tube 50 mayfurther be provided with a fluid control element 53, as show mostclearly in FIGS. 13 and 14. Fluid control element 53 includes a normallyclosed first end 54 and an open second end 56. First and second ends 54,56 are separated by a body portion 58. First end 54 further includes oneor more incisions 78 a that forms multiple cusps 78 b in fluid controlelement 53. Fluid control element 53 is sized so as to fit over a distalend of aspiration tube 50. When the aspiration tube 50 is in a first,retracted position, an open end of aspiration tube 50 is positioned bodyportion 58 of fluid control member 53 such that incisions 78 a remainclose together in their normally closed position. When aspiration tube50 is in a second position, an open end of aspiration tube 50 extendsthrough first end 54, opening incisions 78 a.

Body tissue and fluids are discharged into the collection trap 55, via avacuum line (not shown) that is secured to an end 57 of collection trap55. However, following a biopsy cycle, vacuum in the system is relievedcreating the potential for body fluids to reflux into collection trap55. When this occurs, when collection trap 55 is detached from handpiece12 (to be discussed in further detail below), the excess fluid buildupwithin collection trap 55 increases the potential for blood and otherbody fluid to leak onto the floor, underlying equipment and deviceusers, thereby increasing clean-up time and exposure to potentiallyinfectious materials. FIG. 4E illustrates yet another embodiment of afluid control element 69 that is positioned in collection trap 55 tominimize the likelihood of fluid reflux. In the embodiment shown in FIG.4E, the fluid control element 69 is a normally closed duck-bill valve,wherein the profile of fluid control element 69 is elongated andtapering from the distal end to the proximal end. In one embodiment, asshown in FIG. 4F, a front face 69 a of fluid control element 69 mayinclude a single incision 78 a′ that is normally closed but may be urgedopen by the application of vacuum such that fluids are allowed to flowout of collection trap 55, but prevents fluid from refluxing back intothe collection trap 55. In an alternative embodiment, as shown in FIG.4G, the front face 69 a of fluid control element has a small hole 78 a″therein, that is substantially closed. When vacuum is applied, hole 78a″ widens substantially to permit fluid to flow out of collection trap55. However, hole 78 a″ returns to its substantially closed positionwhen vacuum is removed from the system, thereby minimizing reflux ofbodily fluid.

An alternative fluid control element 87 for use with collection trap 55,is shown in FIGS. 4K and 4L. In this embodiment, fluid control element87 is a flapper valve having an outer ring 91 with a slightly domelikecenter portion 92. Center portion 92 is sized so as to have portionsthat are slightly smaller than an opening 101 formed in outer ring 91,thereby defining gaps between center portion 92 and outer ring 91 whenfluid control element 87 is in an uncompressed position.

Fluid control element 87 is positioned over end 57 of collection trap55. A cap 59 is fitted over end 57 of collection trap 55, therebycompressing fluid control element 87 such that the gaps between centerportion 92 and outer ring 91 are sealed.

FIGS. 4H and 4I illustrate front plan views of alternative embodimentsof fluid control elements 85, 85′ respectively, disposed within an outercannula hub 75 taken along lines 4-4 of FIGS. 3A and 3B. Fluid controlelements 85, 85′ are both normally closed. Each include a number ofincisions 78 a therein that forms multiple cusps 78 b for controllingfluid flow. It is contemplated by the present invention that incision 78a may have a variety of patterns and is not limited to the foregoingembodiments. The specific pattern of incisions 78 a is dependent uponthe design and functional requirements of the biopsy apparatus. In theseembodiments, the fluid control elements 85, 85′ are securely positionedwithin a groove 75 a of hub 75. FIG. 4J shows a perspective view of hub75 having the inner cannula 17 disposed within the outer lumen 27. Asillustrated, the cusps 78 b overlay the outer lumen 27. Having the cusps78 b overlay the outer lumen 27 enables greater fluid control betweenthe inner cannula 17 and the outer cannula 15.

Referring back to FIGS. 2, 3A, and 3B, the aspiration tube 50communicates with the collection trap 55 that is removably mounted tothe handpiece 12. The collection trap 55 includes a pilot port 107 thatis connected by appropriate tubing to the hydraulic control system 150(FIG. 11), as described in more detail herein. For the present purposes,it is understood that a vacuum or aspiration pressure is drawn throughthe pilot port 107 and the collection trap 55. This vacuum then draws atissue sample excised at the working end of the cutting element 11, allthe way through the inner cannula 17, tubular axle 43 and aspirationtube 50 until it is deposited within the trap. Details of the collectiontrap 55 will be discussed herein.

As explained above, the present invention contemplates an inner cannula17 that performs its cutting operation by both rotary and reciprocatingmotion. Thus, the handpiece 12 supports a reciprocating motor 22. In oneaspect of the invention, both motors 20 and 22 are hydraulicallypowered, most preferably pneumatically. This feature allows the motorsto be formed of plastic, since no electrical components are required. Infact, with the exception of the outer cannula 15, trocar tip 16 andinner cannula 17, every component of the biopsy apparatus 10 inaccordance with the present invention can be formed of a non-metallicmaterial, most preferably a medical grade plastic. Thus, the biopsyapparatus 10 is eminently compatible with surgical imaging systems thatmay be used during the biopsy procedure. The compatibility of theapparatus 10 with Magnetic Resonance Imaging (MRI) is important becauseMRI is currently the only non-invasive visualization modality capable ofdefining the margins of the tumor. In addition, since the biopsyapparatus is formed of a relatively inexpensive plastic (as opposed to amore expensive metal), the entire apparatus can be disposable. Moreover,the elimination of substantially all metal components reduces theoverall weight of the handpiece 12, making it very easily manipulated bythe surgeon.

Referring most specifically to FIGS. 3A and 3B, the reciprocating motor22 includes a pneumatic cylinder 60. The cylinder 60 includes a pilotport 61 that connects the cylinder to the hydraulic control system 150through appropriate tubing. The motor 22 includes a piston 63 thatreciprocates within the cylinder 60 in response to hydraulic fluidpressure provided at the pilot port 61. The piston 63 includes a centralbore 64 for mounting the piston 63 to the aspiration tube 50. In oneembodiment, the aspiration tube 50 is press-fit within the bore 64. Theengagement between the aspiration tube 50 and the piston 63 can beenhanced by use of a set screw (not shown) or an adhesive or epoxy. Atany rate, it is essential that the aspiration tube 50 and piston 63 movetogether, since the motor 22 must eventually drive the inner cannula 17axially within the outer cannula.

It should be understood that in addition to powering the inner cannula,the piston 63 also reciprocates the rotary motor 20, which isessentially mounted to the reciprocating aspiration conduit. Thismovement is depicted by comparing the position of the rotary motor 20between FIG. 3A and FIG. 3B. More specifically, the motor 20 as well asthe aspiration conduit, including the inner cannula 17, moves within thehandpiece 12. Preferably, the handpiece housing 70 is provided withopenings 73 (FIG. 3B) at its opposite ends for slidably supporting theaspiration tube 50 and inner cannula 17. Since the distal housing 70 ispreferably formed of a plastic material, no thrust bearings or rotarybearings are necessary to accommodate low friction axial movement of thecannula through the housing openings 73.

The biopsy apparatus 10 includes the handpiece 12 that carries all ofthe operating components and supports the outer and inner cannulas. Thehandpiece 12 includes a distal housing 70 within which is disposed therotary motor 20. The distal end 71 of the housing 70 is configured intoa fitting 72. This fitting 72 engages a mating flange 77 on outercannula hub 75. The hub 75 supports the outer cannula 15 within anengagement bore 76 (see FIG. 3B).

In accordance with one aspect of the present invention, the engagementbetween the outer cannula hub 75 and the distal end 71 of the housing 70need not be airtight. In other words, the mating components of thefitting between the two parts need not be capable of generating afluid-tight seal. In accordance with one embodiment of the invention,the engagement between the hub 75 and the housing 70 for supporting theouter cannula 15 provides a leak path through the outer lumen 27 to theatmosphere. Accordingly, as discussed above, placement and/orintegration of the fluid control element 78 on the hub 75 provides forincreased control of the leak path through the outer lumen 27.

In the use of the tissue biopsy apparatus 10, providing aspirationthrough the inner lumen 34 of the inner cutting cannula 17 will drawtissue through the inner lumen. As the tissue advances farther along thelumen, in some instances a vacuum can be created behind the advancingtissue. At some point in these instances, the tissue will stop advancingalong the length of the inner lumen 34 because the vacuum behind thetissue sample equals the vacuum in front of the tissue sample that isattempting to draw the sample to the collection trap 55. Thus, the leakpath through the outer lumen 27 allows atmospheric air to fall in behindthe tissue sample when the inner cutter is retracted from the cuttingboard. The atmospheric air helps to relieve the vacuum behind theadvancing tissue and aids in drawing the tissue down the length of theaspiration channel to the collection trap 55. However, in someapplications, particularly where smaller “bites” of the target tissueare taken, the atmospheric air leak path is not essential.

Preferably the fitting 72 and the mating flange 77 can be engaged bysimple twisting motion, most preferably via Luer-type fittings. In use,the cannula hub 75 is mounted on the handpiece 12, thereby supportingthe outer cannula 15. The handpiece can then be used to project theouter cannula into the body adjacent the sample site. In certain uses ofthe biopsy apparatus 10, it is desirable to remove the handpiece 12 fromthe cannula hub 75 leaving the outer cannula 15 within the patient. Forexample, the outer cannula 15 can be used to introduce an anesthetic. Inother applications, once the target tissue has been completely excised,the outer cannula 15 can be used to guide a radio-opaque marker to markthe location the removed material.

Returning again to the description of the housing 70, the housingdefines an inner cavity 79 that is open through an access opening 81.The access opening 81 is preferably provided to facilitate assembly ofthe tissue biopsy apparatus 10. The distal end 71 of the housing 70 canbe provided with a pair of distal braces 80 that add stiffness to thedistal end 71 while the apparatus is in use. The braces 80 allow thedistal housing 70 to be formed as a thin-walled plastic housing. Similarbraces can be provided at the opposite end of the distal housing asnecessary to add stiffness to the housing.

The distal housing is configured to support the reciprocating motor 22and in particular the cylinder 60. Thus, in one embodiment of theinvention, the proximal end 83 of the distal housing 70 defines apressure fitting 84. It is understood that this pressure fitting 84provides a tight leak-proof engagement between the distal end 88 of thecylinder 60 and the proximal end 83 of the housing. In one specificembodiment, the pressure fitting 84 forms a spring cavity 85 withinwhich a portion of the return spring 66 rests. In addition, in aspecific embodiment, the pressure fitting 84 defines distal piston stop86. The piston 63 contacts these stops at the end of its stroke. Thelocation of the piston stop 86 is calibrated to allow the cutting edge35 to contact the cutting board 31 at the working end of the cuttingelement 11 to allow the cutting edge to cleanly sever the biopsy tissue.

In the illustrated embodiment, the cylinder 60 is initially provided inthe form of an open-ended cup. The open end, corresponding to distal end88, fastens to the pressure fitting 84. In specific embodiments, thepressure fitting can include a threaded engagement, a press-fit or anadhesive arrangement.

The cylinder cup thus includes a closed proximal end 89. This proximalend defines the pilot port 61, as well as a central opening 62 (FIG. 3B)through which the aspiration tube 50 extends. Preferably, the proximalend 89 of the cylinder 60 is configured to provide a substantiallyairtight seal against the aspiration tube 50 even as it reciprocateswithin the cylinder due to movement of the piston 63. The proximal end89 of the cylinder 60 defines a proximal piston stop 90, which caneither be adjacent the outer cylinder walls or at the center portion ofthe proximal end. This proximal piston stop 90 limits the reverse travelof the piston 63 under action of the return spring 66 when pressurewithin the cylinder has been reduced.

In a further aspect of the invention, the collection trap 55 is mountedto the handpiece 12 by way of a support housing 93. It should beunderstood that in certain embodiments, the handpiece 12 can be limitedto the previously described components. In this instance, the collectiontrap 55 can be situated separate and apart from the handpiece,preferably close to the source of vacuum or aspiration pressure. In thiscase, the proximal end of the aspiration tube 50 would be connected tothe collection trap 55 by a length of tubing. In the absence of thecollection trap 55, the aspiration tube 50 would reciprocate away fromand toward the proximal end of the cylinder 60, so that it is preferablethat the handpiece includes a cover configured to conceal thereciprocating end of the aspiration tube.

However, in accordance with one embodiment, the collection trap 55 isremovably mounted to the handpiece 12. A pair of longitudinallyextending arms 94 that define an access opening 95 therebetween, formsthe support housing 93. The support housing 93 includes a distal endfitting 96 that engages the proximal end 89 of cylinder 60. A variety ofengagements are contemplated, preferably in which the connection betweenthe two components is generally airtight. The proximal end 97 of thesupport housing 93 forms a cylindrical mounting hub 98. As best shown inFIG. 1, the mounting hub 98 surrounds a proximal end of the collectiontrap 55. The hub forms a bayonet-type mounting groove 99 that receivespins 103 attached to the housing 102 of the trap 55. A pair ofdiametrically opposite wings 104 can be provided on the housing 102 tofacilitate the twisting motion needed to engage the bayonet mountbetween the collection trap 55 and the support housing 93. While oneembodiment contemplates a bayonet mount, other arrangements forremovably connecting the collection trap 55 to the support housing 93are contemplated. To be consistent with one of the features of theinvention, it is preferable that this engagement mechanism be capable ofbeing formed in plastic.

In order to accommodate the reciprocating aspiration tube, the supporthousing 93 is provided with an aspiration passageway 100 that spansbetween the proximal and distal ends of the housing. Since theaspiration tube 50 reciprocates, it preferably does not extend into thecollection trap 55. As excised tissue is drawn into the trap 55, areciprocating aspiration tube 50 can contact the biopsy materialretained within the trap. This movement of the tube can force tissueinto the end of the tube, clogging the tube. Moreover, the reciprocationof the aspiration tube 50 can compress tissue into the end of the trap,thereby halting the aspiration function.

The collection trap 55 includes a housing 102, as previously explained.The housing forms a pilot port 107, which is connectable to a vacuumgenerator. Preferably in accordance with the present invention,appropriate tubing to the hydraulic control system 150 (FIG. 10)connects the pilot port 107. As illustrated in FIGS. 3A and 3B, the trap55 may also contain the fluid control element 78. The fluid controlelement 78 having the profile illustrated in FIG. 4E is preferred,although any profile illustrated herein would also function inaccordance with the present invention. Accordingly, the cusps 78 b atthe tapered end of fluid control element 78 extend out of the pilot port107. Thus, fluid flow from the trap 55 through pilot port 107 is impededby the tapering construction of fluid control element 78. It is alsocontemplated that the fluid control element 78 shown in FIGS. 4C and 4Dmay be incorporated the trap 55.

Body tissue and fluids are discharged into the collection trap 55. Thecollection trap 55 must access the interior thereof to obtain tissuesamples. However, because the aspiration passage 100 would be open tothe environment when the collection trap 55 is accessed, there is agreat potential for blood and body fluid to leak unto the floor,underlying equipment and device users, thereby increasing clean-up timeand increasing exposure to potentially infectious materials.Accordingly, the collection trap 55 may also include a fluid controlelement 109 (best seen in FIGS. 4M-4Q) mounted within mounting hub 98,as shown in FIGS. 3A and 3B. Fluid control element 109 includes aspring-like body member 113 that has a supporting flange 113 a, and anormally closed valve component 114. Valve component 114 includes one ormore incisions 78 a therein that form cusps 78 b when fluid controlelement 109 is compressed into an open position. The cusps 78 b surrounda passageway 116 that is created by the compression of fluid controlelement 109. The fluid control element 109 is mounted within mountinghub 98 such that a bottom surface 119 is positioned in contact withaspiration tube 100 and valve component 114 contacts an interior wall ofmounting hub 98. When collection trap 55 is connected to mounting hub98, body member 113 is compressed, as shown in FIG. 4P. The incisions 78a split apart thereby defining passageway 116 that is surrounded bycusps 78 b. When collection trap 55 is detached from mounting hub 98,the body member 113 recoils and returns to its normally closed positionthereby closing off aspiration tube 100 from the environment to reducethe potential for leakage.

The trap 55 further includes a filter element 110 mounted within thetrap. In one embodiment, the filter element is a mesh filter that allowsready passage of air, blood and other fluids, while retaining excisedbiopsy tissue samples, and even morcellized tissue. In addition, thefilter element 110 is preferably constructed so that vacuum oraspiration pressure can be drawn not only at the bottom end of thefilter element, but also circumferentially around at least a proximalportion of the element 110. In this way, even as material is drawntoward the proximal end of the filter, a vacuum can still be drawnthrough other portions of the filter, thereby maintaining the aspirationcircuit.

The handpiece 12 can include individual covers for closing the accessopening 81 in the distal housing 70 and the access openings 95 in thesupport housing 93. Those covers can support tubing for engagement withthe pilot ports 40 and 61. Alternatively and most preferably, a singlecover 13 as depicted in FIG. 5, is provided for completely enclosing theentire handpiece. The distal end 71 of the housing 70 can define anumber of engagement notches 115 equally spaced around the perimeter ofthe distal end. The handpiece cover 13 can then include a like number ofequally distributed tangs 117 projecting inwardly from the inner surface118.

These tangs are adapted to snap into the engagement notches 115 to holdthe cover 13 in position over the handpiece 12. The cover can beattached by sliding axially over the handpiece 12. The cover 13 caninclude fittings for fluid engagement with the two pilot ports 40 and61. Alternatively, the cover can be formed with openings for insertionof engagement tubing to mate with the respective pilot ports to providehydraulic fluid to the rotary motor 20 and the reciprocating motor 22.In an specific embodiment, the cover 13 extends from the distal end 71of the distal housing 70 to the proximal end 97 of the support housing93. The cover can thus terminate short of the bayonet mounting featurebetween the support housing and the collection trap 55. Although notshown in the figures, the proximal end 97 of the support housing 93 canbe configured to include a similar array of engagement notches with acorresponding array of mating tangs formed at the proximal end of thecover 13.

Referring now to FIGS. 7-9, alternative embodiments of the outer cannulaare depicted. As shown in FIG. 7 an outer cannula 125 includes atissue-receiving opening 126. The opening is formed by oppositelongitudinal edges 127. In one specific embodiment, a number of teeth129 are formed at each longitudinal edge 127. As depicted in the figure,the teeth are proximally facing—i.e., away from the cutting board 31(not shown) at the distal end of the outer cannula. With thisorientation, the teeth 129 help prevent forward motion of tissue drawninto the opening 126 as the inner cannula 17 moves forward toward thecutting board. In prior devices, as the reciprocating cutting elementadvances through the outer cannula, the cutting edge not only starts tosever the tissue, it also pushes tissue in front of the inner cannula.Thus, with these prior devices, the ultimate length of the biopsy sampleretrieved with the cut is smaller than the amount of tissue drawn intothe tissue-receiving opening of the outer cannula. With the teeth 129 ofthe outer cannula 125 of this embodiment of the invention, the tissuesample removed through the inner cannula 17 is substantially the samelength as the tissue-receiving opening 126. As the inner cannula 17advances into the tissue, each of the teeth 129 tends to hold the tissuein place as the cutting edge 35 severs the tissue adjacent the outercannula wall. With this feature, each “bite” is substantially as largeas possible so that a large tissue mass can be removed with much fewer“bites” and in a shorter period of time. In addition to supporting thesubject tissue as the inner cannula advances, the teeth can also cutinto the tissue to prevent it from retracting out of the opening as theinner cutting cannula 17 advances.

The outer cannula 125 depicted in FIG. 7 can also incorporate astiffening element 131 opposite the tissue-receiving opening 126. Thestiffening element 131 adds bending stiffness to the outer cannula 125at the distal end in order to maintain the longitudinal integrity of theouter cannula 125 as it is advanced into a tissue mass. In some priordevices that lack such a stiffening element, the working end of thecutting device is compromised as it bends slightly upward or downward asthe outer cannula passes into the body. This bending can either close orexpand the tissue-receiving opening, which leads to difficulties inexcising and retrieving a tissue sample. The cutting mechanism of thepresent invention relies upon full, flush contact between the cuttingedge of the inner cannula 17 and the cutting board 31. If the end of theouter cannula 125 is slightly askew, this contact cannot be maintained,resulting in an incomplete slice of the tissue sample.

As depicted in the cross-sectional view of the FIG. 8, the stiffeningelement 131 in one embodiment is a crimp extending longitudinally in theouter wall of the cannula substantially coincident with thetissue-receiving opening 126. The outer cannula 125′ depicted in FIG. 8shows two additional versions of a stiffening element. In both cases, abead of stiffening material is affixed to the outer cannula. Thus in onespecific embodiment, a bead 131′ is adhered to the inner wall of theouter cannula. In a second specific embodiment, a bead 131″ is affixedto the outside of the outer cannula. In either case, the beads can beformed of a like material with the outer cannula, and in both cases, thebeads provide the requisite additional bending stiffness. Anotherversion of a stiffening element is shown if FIG. 9A. In this case, alayer 131′″ of additional stainless steel is bonded to the outer wall ofthe outer cannula 125″.

Returning to FIG. 7, a further feature that can be integrated into theouter cannula 125 is the dimple 135. One problem frequently experiencedby tube-within-a-tube cutters is that the inner reciprocating cutterblade contacts or catches on the outer cannula at the distal edge of thetissue-receiving opening. With the present invention, the dimple 135urges the inner cannula 17 away from the tissue-receiving opening 126.In this way, the dimple prevents the cutting edge of the inner cannula17 from catching on the outer cannula as it traverses thetissue-receiving opening. In the illustrated embodiment of FIG. 7, thedimple 135 is in the form of a slight crimp in the outer cannula 125.Alternatively, as with the different embodiments of the stiffeningelement, the dimple 135 can be formed by a protrusion affixed or adheredto the inner surface of the outer cannula. Preferably, the dimple 135 issituated immediately proximal to the tissue-receiving opening to helpmaintain the distance between the cutting edge and the tissue-receivingopening.

As previously described, the outer cannula 15 is supported by a hub 75mounted to the distal end of the handpiece. In an alternative embodimentdepicted in FIG. 10, the outer cannula hub 140 provides a mean forintroducing fluids into the outer lumen 27 of the outer cannula. Thus,the hub 140 includes an engagement bore 141 within which the outercannula 15 is engaged. The hub also defines a flange 142 configured formating with the fitting 72 at the distal end 71 of the housing 70. Thus,the outer cannula hub 140 is similar to the hub 75 described above. Withthis embodiment, however, an irrigation fitting 145 is provided. Thefitting defines an irrigation lumen 146 that communicates with theengagement bore 141.

Ultimately, this irrigation lumen is in fluid communication with theouter lumen 27 of the outer cannula 15. The irrigation fitting 145 canbe configured for engagement with a fluid-providing device, such as asyringe. The hub 140 thus provides a mechanism for introducing specificfluids to the biopsy site. In certain procedures, it may be necessary tointroduce additional anesthetic to the sampling site, which can bereadily accommodated by the irrigation fitting 145.

As discussed above, in one embodiment of the tissue biopsy apparatus 10according to the present invention relies upon hydraulics or pneumaticsfor the cutting action. Specifically, the apparatus includes a hydraulicrotary motor 20 and a hydraulic reciprocating motor 22. While theapparatus 10 can be adapted for taking a single biopsy slice, thepreferred use is to completely remove a tissue mass through successivecutting slices. In one typical procedure, the cutting element 11 ispositioned directly beneath a tissue mass, while an imaging device isdisposed above the mass. The imaging device, such as an ultra-soundimager, provides a real-time view of the tissue mass as the tissuebiopsy apparatus 10 operates to successively remove slices of the mass.Tissue is continuously being drawn into the cutting element 11 by theaspiration pressure or vacuum drawn through the inner cannula 17.Successive reciprocation of the inner cannula 17 removes large slices ofthe mass until it is completely eliminated.

In order to achieve this continuous cutting feature, the presentinvention contemplates a hydraulic control system 150, as illustrated inthe diagram of FIG. 11. Preferably the bulk of the control system ishoused within a central console. The console is connected to apressurized fluid source 152. Preferably the fluid source provides aregulated supply of filtered air to the control system 150.

As depicted in this diagram of FIG. 11, pressurized fluid from thesource as provided at the several locations 152 throughout the controlsystem. More specifically, pressurized fluid is provided to five valvesthat form the basis of the control system.

At the left center of the diagram of FIG. 11, pressurized fluid 152passes through a pressure regulator 154 and gauge 155. The gauge 155 ispreferably mounted on the console for viewing by the surgeon or medicaltechnician. The pressure regulator 154 is manually adjustable to controlthe pressurized fluid provided from the source 152 to the two-positionhydraulic valve 158. The valve 158 can be shifted between a flow path158 a and a flow path 158 b. A return spring 159 biases the hydraulicvalve to its normal position 158 a.

In the normally biased position of flow path 158 a, the valve 158connects cylinder pressure line 161 to the fluid source 152. Thispressure line 161 passes through an adjustable flow control valve 162that can be used to adjust the fluid flow rate through the pressure line161. Like the pressure gauge 155 and pressure regulator 154, theadjustable flow control valve 162 can be mounted on a console formanipulation during the surgical procedure.

The pressure line 161 is connected to the pilot port 61 of thereciprocating motor 22. Thus, in the normal or initial position of thehydraulic control system 150, fluid pressure is provided to the cylinder60 to drive the piston 63 against the biasing force of the return spring66. More specifically with reference to FIG. 3B, the initial position ofthe hydraulic valve 158 is such that the reciprocating motor and innercannula are driven toward the distal end of the cutting element. In thisconfiguration, the inner cannula 17 covers the tissue-receiving opening25 of the outer cannula 15. With the inner cannula so positioned, theouter cannula can be introduced into the patient without risk of tissuefilling the tissue-receiving opening 25 prematurely.

Pressurized fluid along cylinder pressure line 161 is also fed to apressure switch 165. The pressure switch has two positions providingflow paths 165 a and 165 b. In addition, an adjustable return spring 166biases this switch to its normal position at which fluid from thepressure source 152 terminates within the valve. However, whenpressurized fluid is provided through cylinder pressure line 161, thepressure switch 165 moves to its flow path 165 b in which the fluidsource 152 is hydraulically connected to the pressure input line 168.This pressure input line 168 feeds an oscillating hydraulic valve 170.It is this valve that principally operates to oscillate thereciprocating motor 22 by alternately pressurizing and releasing thetwo-position hydraulic valve 158. The pressure switch 165 is calibratedto sense an increase in pressure within the cylinder pressure line 161or in the reciprocating motor cylinder 60 that occurs when the piston 66has reached the end of its stroke. More specifically, the piston reachesthe end of its stroke when the inner cannula 17 contacts the cuttingboard 31. At this point, the hydraulic pressure behind the pistonincreases, which increase is sensed by the pressure valve 165 to strokethe valve to the flow path 165 b.

The oscillating hydraulic valve 170 has two positions providing flowpaths 170 a and 170 b. In position 170 a, input line 179 is fed tooscillating pressure output line 172. With flow path 170 b, the inputline 179 is fed to a blocked line 171. Thus, with fluid pressureprovided from pressure switch 165 (through flow path 165 b), theoscillating valve 170 opens flow path 170 a which completes a fluidcircuit along output line 172 to the input of the hydraulic valve 158.

Fluid pressure to output line 172 occurs only when there is fluidpressure within input line 179. This input line is fed by valve 176,which is operated by foot pedal 175. The valve 176 is biased by a returnspring 177 to the initial position of flow path 176 a. However, when thefoot pedal 175 is depressed, the valve 176 is moved against the force ofthe spring to flow path 176 b. In this position, pressurized fluid fromthe source 152 is connected to the foot pedal input line 179. When theoscillating hydraulic valve 170 is in its initial position flow path 170a, pressurized fluid then flows through input line 179 to output line172 and ultimately to the hydraulic valve 158.

The fluid pressure in the output line 172 shifts the valve 158 to theflow path 158 b. In this position, the fluid pressure behind the piston63 is relieved so that the return spring 66 forces the piston toward theproximal end. More specifically, the return spring retracts the innercannula 17 from the tissue cutting opening 25. The relief of the fluidpressure in line 161 also causes the pressure switch 165 to return toits initial neutral position of flow path 165 a, due to the action ofthe return spring 166. In turn, with the flow path 165 a, the pressureinput line 168 is no longer connected to the fluid source 152, so nopressurized fluid is provided to the oscillating hydraulic valve 170.Since this valve is not spring biased to any particular state, itsposition does not necessarily change, except under conditions describedherein.

Returning to the foot pedal 175 and valve 176, once the foot pedal isreleased, the biasing spring 177 forces the valve 176 from its flow path176 b to its normal initial flow path 176 a. In this position the footpedal input line 179 is no longer connected to the fluid source 152.When the oscillating valve 170 is at flow path 170 a, the fluid pressurethrough output line 172 is eliminated. In response to this reduction influid pressure, hydraulic valve 158 is shifted to its original flow path158 a by operation of the return spring 159. In this position, thecylinder pressure line 161 is again connected to the fluid source 152,which causes the reciprocating motor 22 to extend the inner cannula 17to its position blocking the tissue-receiving opening 25. Thus, inaccordance with the present invention, the hydraulic control system 150starts and finishes the tissue biopsy apparatus 10 with thetissue-receiving opening closed. It is important to have the openingclosed once the procedure is complete so that no additional tissue maybe trapped or pinched within the cutting element 11 as the apparatus isremoved from the patient.

Thus far the portion of the hydraulic control system 150 that controlsthe operation of the reciprocating motor 22 has been described. Thesystem 150 also controls the operation of the rotary motor 20. Again, inone embodiment, the motor 20 is an air motor. This air motor iscontrolled by another hydraulic valve 182. As show in FIG. 11, theinitial position of the valve provides a flow path 182 a in which thefluid source 152 is connected to blocked line 183. However, when thehydraulic valve 182 is pressurized, it moves to flow path in which thefluid source 152 is connected to the pilot port 40 of the air motor. Inthis position, pressurized fluid continuously drives the air motor 20,thereby rotating the inner cannula 17. It can be noted parentheticallythat a muffler M can be provided on the air motor to reduce noise.

The rotary motor hydraulic valve 182 is controlled by fluid pressure onpressure activation line 180. This activation line 180 branches from thefoot pedal input line 179 and is connected to the foot pedal switch 176.When the foot pedal 175 is depressed, the switch moves to its flow path176 b. In this position the pressure activation line 180 is connected tothe fluid source 152 so fluid pressure is provided directly to therotary motor hydraulic valve 182. As with the other hydraulic valves,the valve 182 includes a biasing spring 184 that must be overcome by thefluid pressure at the input to the valve.

It should be understood that since the fluid control for the rotarymotor 20 is not fed through the oscillating hydraulic valve 170, themotor operates continuously as long as the foot pedal 175 is depressed.In addition, it should also be apparent that the speed of the rotarymotor 20 is not adjustable in the illustrated embodiment. Since themotor 20 is connected directly to the fluid source 152, which ispreferably regulated at a fixed pressure, the air motor actuallyoperates at one speed. On the other hand, as discussed above, thereciprocating motor 22 is supplied through a pressure regulator 154 anda flow control valve 162. Thus, the speed of reciprocation of thecutting blade 35 is subject to control by the surgeon or medicaltechnician. The reciprocation of the cutting element 11 can be afunction of the tissue being sampled, the size of the tissue biopsysample to be taken, and other factors specific to the particularpatient. These same factors generally do not affect the slicingcharacteristic of the cutting edge 35 achieved by rotating the innercannula.

The hydraulic control system 150 also regulates the aspiration pressureor vacuum applied through the aspiration conduit, which includes theinner cannula 17. In the illustrated embodiment, the pressure activationline 180 branches to feed an aspiration valve 185. The valve is movablefrom its initial flow path 185 a to a second flow path 185 b. In theinitial flow path, the fluid source 152 is connected to a blocked line186. However, when fluid pressure is applied on line 180, the valve 185shifts against the biasing spring 187 to the flow path 185 b. In thispath, the venturi element 190 is connected to the fluid source. Thisventuri element thus generates a vacuum in a vacuum control line 193 andin aspiration line 191. Again, as with the air motor, the venturielement 190 can include a muffler M to reduce noise within thehandpiece.

As long as the foot pedal 175 is depressed and the valve 176 is in itsflow path 176 b, fluid pressure is continuously applied to theaspiration hydraulic valve 185 and the venturi element 190 generates acontinuous vacuum or negative aspiration pressure. As with the operationof the rotary motor, this vacuum is not regulated in all embodiments.However, the vacuum pressure can be calibrated by a selection of anappropriate venturi component 190.

When the venturi component 190 is operating, the vacuum drawn on controlline 193 operates on vacuum switch 194. A variable biasing spring 195initially maintains the vacuum switch 194 at its flow path 194 a. Inthis flow path, the vacuum input line 196 is not connected to any otherline. However, at a predetermined vacuum in control line 193, the valvemoves to flow path 194 b. In this position, the vacuum input line 196 isconnected to pressure line 192. In one embodiment, the vacuum switch 194operates in the form of a “go-nogo” switch in other words, when theaspiration vacuum reaches a predetermined operating threshold, thevacuum switch is activated. When the vacuum switch 194 is initiallyactivated, it remains activated as along as the foot pedal is depressed.Thus vacuum input line 196 is continuously connected to pressure line192 as long as the foot pedal 175 is depressed.

Looking back to the hydraulic valve 158, the fluid pressure in line 192,and ultimately in vacuum input line 196, is determined by the state ofvalve 158. When the valve 158 is in its flow path 158 a in whichregulated fluid pressure is provided to the reciprocating motor 22, thepressure line 192 is dead. However, when the valve 158 moves to flowpath 158 b, pressure line 192 is connected to the regulated fluidsource. Pressurized fluid then flows from pressure line 192, throughvacuum switch flow path 194 b, through vacuum input line 196 to the leftside of oscillating valve 170, causing the valve to stroke to flow path170 b. When the oscillating valve 170 is in this flow path, output line172 is dead, which allows valve 158 to move to its flow path 158 a underthe effect of the return spring 159. In this state, valve 158 allowspressurized fluid to again flow to the reciprocating motor 22 causing itto move through the next cutting stroke.

Thus, when both the valve 158 and the vacuum switch 194 are moved totheir alternate states, pressurized fluid passes from line 192, throughvacuum input line 196, and through an adjustable flow control valve 197to a second input for the oscillating hydraulic valve 170. Pressure onthe vacuum input line 196 shifts the oscillating valve 170 to its secondposition for flow path 170 b. In this position, pressurized fluidpassing through the foot pedal valve 176 terminates within valve 170. Asa consequence, the pressure in output line 172 drops which allows thehydraulic valve 158 shift back to its original position 158 a underoperation of the return spring 159. In this position, fluid pressure isagain supplied to the reciprocating motor 22 to cause the piston 66 tomove through its cutting stroke.

It should be appreciated that the oscillating valve 170 is influenced byfluid pressure on lines 168 and 196, and that these lines will not befully pressurized at the same time. When the system is initiallyenergized, pressure from source 152 is automatically supplied toreciprocating motor 22 and pressure valve 165, causing the valve to moveto flow path 165 b. In this state, line 168 is pressurized which shiftsoscillating valve 170 to the left to state 170 a. The oscillating valvewill remain in that state until line 196 is pressurized, regardless ofthe position of pressure switch 165. It can also be appreciated that inone embodiment, the fluid pressure on line 196 does not increase tooperating levels until the foot pedal 175 has been depressed and theaspiration circuit has reached its operating vacuum.

In an alternative embodiment, the vacuum switch 194 can be calibrated tosense fine changes in vacuum. In this alternative embodiment, thecompletion of this return stroke can be determined by the state of thevacuum switch 194. The vacuum switch 194 can operate as an indicatorthat a tissue sample has been drawn completely through the aspirationconduit into the collection trap 55. More specifically, when the vacuumsensed by vacuum switch 194 has one value when the inner cannula is opento atmospheric pressure. This vacuum pressure changes when a tissuesample is drawn into the inner cannula 17. The vacuum pressure changesagain when the tissue is dislodged so that the inner cannula is againopen to atmospheric pressure. At this point, the inner cannula 17 isclear and free to resume a cutting stroke to excise another tissuesample. Thus, the vacuum switch 194 can stroke to its flow path 194 b toprovide fluid pressure to the left side of the oscillating valve 170,causing the valve to stroke to flow path 170 b.

It can be appreciated from this detail explanation that the hydrauliccontrol system 150 provides a complete system for continuouslyreciprocating the axial motor 22. In addition, the system providesconstant continuous pressure to both the rotary motor 20 and theaspiration line 191, so long as the foot pedal 175 is depressed. Oncethe foot pedal is released, fluid pressure in activation line 180 dropswhich causes the air motor control valve 182 and the aspiration controlvalve 185 to shift to their original or normal positions in which fluidpressure is terminated to those respective components. However, in oneembodiment, pressure is maintained to the reciprocating motor 22 becausethe motor is fed through valve 158, which is connected directly to thefluid source 152.

The hydraulic control system 150 in the illustrated embodimentincorporates five controllable elements. First, the fluid pressureprovided to activate the reciprocating motor 22 is controlled throughthe regulator 154. In addition, the fluid flow rate to the piston 63 iscontrolled via the adjustable control valve 162. The pressure at whichthe pressure switch 165 is activated is determined by an adjustablereturn spring 166. Likewise, the aspiration pressure vacuum at which thevacuum switch 194 is activated is controlled by an adjustable returnspring 195. Finally the adjustable flow control valve 197 controls thefluid flow from the vacuum switch 194 to the oscillating hydraulic valve170. Each of these adjustable elements controls the rate and duration ofoscillation of the reciprocating motor 22.

In one embodiment, the pressure switch 165 essentially operates as an“end of stroke” indicator. In other words, when the inner cannula 17reaches the end of its forward or cutting stroke, it contacts thecutting board 31. When it contacts the cutting board, the pressure inthe cylinder pressure line 161 changes dramatically. It is this changethat causes the pressure switch 165 to change states. This state changecauses the oscillating valve 170 to shift valve 158 to terminate fluidpressure to the motor 22, causing it to stop its cutting stroke andcommence its return stroke.

During this return stroke, the excised tissue sample is gradually drawnalong the aspiration conduit. Also during the return stroke, fluidpressure bleeds from pressure line 161 and pressure switch 165 andultimately from line 168 feeding oscillating valve 170. When this valvestrokes, fluid pressure bleeds from valve 158 allowing the valve toreturn to state 158 a to pressurize the motor 22 for a new cuttingstroke. The operation of each of these hydraulic valves introduces aninherent time delay so that by the time the pressure to thereciprocating motor 22 has been restored the aspiration vacuum haspulled the tissue sample through the entire aspiration conduit and intothe collection trap 55.

The use of a hydraulically controlled inner cutting cannula providessignificant advantages over prior tissue cutting devices. The use ofhydraulics allows most of the operating components to be formed ofinexpensive and light-weight non-metallic materials, such asmedical-grade plastics. The hydraulic system of the present inventioneliminates the need for electrical components, which means thatelectrical insulation is unnecessary to protect the patient.

Perhaps most significantly, the hydraulically controlled reciprocationof the inner cutting cannula provides a cleaner and better-controlledcut of biopsy tissue. Since the reciprocating motor 22 is fed from asubstantially constant source of pressurized fluid, the pressure behindthe motor piston 63 remains substantially constant throughout thecutting stroke. This substantially constant pressure allows the innercutting cannula to advance through the biopsy tissue at a ratedetermined by the tissue itself.

In other words, when the cutting edge 35 encounters harder tissue duringa cutting stroke, the rate of advancement of the motor piston 63 andtherefore the inner cannula 17 decreases proportionately. This featureallows the cutting edge to slice cleanly through the tissue without therisk of simply pushing the tissue. The rotation of the cutting edge canfacilitate this slicing action. When the inner cannula encounters lessdense tissue, the constant pressure behind the piston 63 allows thecutting edge to advance more quickly through the tissue.

In the alternative embodiment, the rotary motor 20 can consist of anelectric motor, rather than a pneumatic motor. As depicted in FIG. 12,the pressure activation line 180 can be fed to an on-off pressure switch198 that is governed by an adjustable bias spring 199. When theactivation line 180 is pressurized the switch 198 establishes a connectbetween an electric reciprocating motor 22 and a battery pack 200.Preferably, the batter pack 200 is mounted within the handpiece 12, butcan instead be wired to an external battery contained within theconsole.

In one specific embodiment, the tissue biopsy apparatus 10 depicted inFIG. 1 has an overall length of under sixteen inches (16″) and an outerdiameter less than one and one quarter inches (1.25″). The outer cannulaand therefore the cutting element 11 have a length measured from thehandpiece 12 of approximately five inches (5″). The outer cannulapreferably has a nominal outer diameter of 0.148″ and a nominal innerdiameter of 0.136″. The inner cannula most preferably has a nominalouter diameter of 0.126″ so that it can reciprocate freely within theouter cannula without catching on the tissue cutting opening. The innercannula has a nominal wall thickness of 0.010″, which yields a nominalinner lumen diameter of about 0.106″.

The length of the tissue-receiving opening determines the length ofbiopsy sample extracted per each oscillation of the reciprocating motor22. In one specific embodiment, the opening has a length of about 0.7″,which means that a 0.7″ long tissue sample can be extracted with eachcutting cycle. In order to accommodate a large n umber of these biopsytissue slugs, the collection trap can have a length of about 2.5″ and adiameter of about 0.05″. Of course, the interior volume of thecollection trap can vary depending upon the size of each biopsy slug andthe amount of material to be collected. In a specific embodiment, thefilter disposed within the collection trap 55 is manufactured byPerformance Systematix, Inc. of Callondoni, Mich.

In accordance with a specific embodiment, the cutting stroke for theinner cannula is about 0.905″. The return spring 66 within thereciprocating motor 22 is preferably a conical spring to reduce thecompressed height of the spring, thereby allow a reduction in theoverall length of the hydraulic cylinder 60. In addition, the returnspring 66 can be calibrated so that the return stroke occurs in lessthan about 0.3 seconds. Preferably, the inwardly beveled surface 36 ofcutting edge 35 is oriented at an approximately 30° angle.

The aspiration pressure vacuum is nominally set at 27 in.Hg. during thecutting stroke. When the cannula is retracted and the outer lumen 27 isopen, the vacuum pressure is reduced to 25 in.Hg. This aspirationpressure normally allows aspiration of a tissue sample in less thanabout 1 second and in most cases in about 0.3 second. In accordance withone embodiment, the hydraulic control system 150 preferably iscalibrated so that the inner cannula dwells at its retracted positionfor about 0.3 seconds to allow complete aspiration of the tissue sample.Adjusting the return spring 195 of the vacuum switch 194 can controlthis dwell rate.

In one embodiment, the inner cannula 17 can advance through the cuttingstroke in about two seconds. This stroke speed can be accomplished witha regulated pressure at source 152 of about 20 p.s.i. When the innercannula reaches the end of its cutting stroke, the pressure can increaseat about five p.s.i. per second. Preferably, the return spring 166 ofthe pressure switch 165 is set so that the end of cutting stroke issensed within about 0.5 seconds.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character. It should be understoodthat only the preferred embodiments have been shown and described andthat all changes and modifications that come within the spirit of theinvention are desired to be protected.

EXAMPLES Example 1

Eighteen trial biopsies were performed upon patients after obtaininginformed consent and preparing the patients according to standard biopsyprocedures. In each case, biopsies were performed according to thefollowing procedure. The patient was positioned on her back on thesurgical table, and the lesion was located using ultrasound. A smallincision was made in the breast. Wile viewing the lesion usingultrasound, an early embodiment of the present invention was insertedinto the breast with the tissue receiving opening adjacent the lesion.The cutter was engaged to sample and/or remove the lesion. The lesionsvaried in size from 6-22 mm. The surgeon's comments are provided inTable 1. TABLE 1 Surgeon's Comments Regarding the Use of EarlyEmbodiments of the Present Biopsy Device Trial Number Surgeon's Comments1 Went very well, lesion took approximately 50 seconds to go away 2Large fatty breast, very difficult to get needle to mass; eventuallysuccessfully removed 3 Successfully removed without problems 4 Went verywell; lesion gone in 4-5 cores 5 Two lesions attempted (1) lesion easilyremoved, (2) inner cutter was riding up and catching the opening 6 Onlytook 4-5 cores to disappear 7 Started getting good cores, then stoppedcutting due to secondary electrical break 8 Lesion appeared to betotally gone, cores were up to 25 mm in length 9 Only got 4-5 goodcores, then stopped cutting due to inner cutter riding up 10 No problems11 No problems at all 12 Lesion was easily palpable but very mobilewhich made access difficult. Used tactile sensation to manipulate tumorinto aperture which worked very well; very good cores; Took 4.5 minutesbut many of the cores were fatty as a lot of the time I was missing thelesion before realizing that palpitation was better 13 Took 3-4 coresthen quit cutting, blade was dulled, probably due to deflection of tipdownward 14 Went very well, no problems 15 Went well, no problems 16Went well, no problems 17 Went very well 18 Went very well, the suctiontubing collapsed, need stronger tubing; filter did fill up requiringstopping to empty, might need larger filter

Table 1 illustrates the success of the present invention in its earlystage of development. A majority of the trials, trials 1-6, 8, 1-12, and14-18, resulted in a successful removal of the lesion with little to noproblems. Lesions were removed quickly and, in some cases, only a fewcores were required (see trials 1, 4, and 6). In trial number 8 it wasnoted that the cores were up to 25 mm in length.

In some trials, the surgeon experienced difficulties removing the lesionbecause the inner cutting blade would ride up and catch on the tissuereceiving opening (see trials 5, and 9,). However, this problem has beenresolved in the present invention by integrating a crimp in the outercannula. The crimp forms a dimple that protrudes from the inner surfaceof the cannula and into the outer lumen. As the inner cannula passes thedimple, the dimple forces the inner cannula away from thetissue-receiving opening and prevents the inner cannula from riding upinto the opening. In a further embodiment, the cutting edge of the innercannula is inwardly beveled. This inwardly beveled surface also helpseliminate risk of catching by guiding the inner cannula back into thehollow outer cannula. In addition, to prevent the deflection of the tipdownward, as noted in trial 13, a stiffening element is provided on theouter cannula opposite the tissue-receiving opening.

Example 2

Surgeons performing biopsies using the device of this invention and adevice having the features of U.S. Pat. No. 5,526,882 to Burbankprovided feedback as to the efficiency of each device. The surgeons'input was used to calculate the amount of time and the number of strokesnecessary to remove a lesion. Table 2 compares the amount of time andthe number of strokes necessary to remove comparable lesions using eachdevice. TABLE 2 Comparison of Removal Times and Number of Strokes of thePresent Biopsy Device with the Prior Art Device Present Biopsy DevicePrior Art Removal Times (sec) Lesion Diameter 10 80 500 13 135 845 16205 1280 No. of Strokes Lesion Diameter 10 16 25 13 27 42 16 41 64

The data demonstrates that the present tissue biopsy apparatusconsistently removes a lesion with fewer strokes and in less time thanthe prior cutter, the present tissue biopsy device performs 80% fasterthan the prior cutter, which ultimately results in reduced trauma to thetissue.

1. A fluid control element for a biopsy device, comprising: a flexible member connected to the biopsy device and adapted for selective deformation when an element of the biopsy device is inserted therein; wherein said member includes at least one incision that defines at least one cusp that selectively opens when said element is inserted therein, said incision being biased in a normally and substantially closed position to substantially prevent fluids and materials from flowing out of the biopsy device.
 2. An element according to claim 1, wherein said flexible member is constructed of an elastomer material.
 3. An element according to claim 1, wherein said at least one incision forms four cusps.
 4. An element according to claim 1, wherein said at least one incision forms three cusps.
 5. An element according to claim 1, wherein said at least one incision forms two cusps.
 6. An element according to claim 1 wherein said member has an elongated profile.
 7. An element according to claim 6, wherein said elongated profile tapers from a distal end to a proximal end.
 8. An element according to claim 6, wherein said elongated profile has a diameter that is substantially the same from a first end to a second end.
 9. An element according to claim 8, wherein said first end is normally closed and includes said at least one incision therein and said second end is open.
 10. An element according to claim 6, wherein said element includes a flexible body member and a normally closed valve component that includes said at least one incision.
 11. An element according to claim 10, wherein said body member is defined by a first end and a second end, wherein a central opening extends between said first and second ends and said valve component is positioned to substantially cover said first end.
 12. An element according to claim 1, wherein said member has a disk shaped profile.
 13. An element according to claim 1, wherein said at least one incision is in the form of a substantially closed opening positioned approximately in the center of said element.
 14. A fluid control element for a biopsy device, comprising: a flexible member connected to the biopsy device and adapted for selective deformation when an element of the biopsy device is inserted therein; wherein said member includes an outer ring portion and a central portion that includes at least one opening that is normally open when said member is in an uncompressed position, said opening being substantially closed off when said member is in a compressed position.
 15. An element according to claim 14, wherein said central portion has an upwardly extending concave configuration.
 16. An element according to claim 15, wherein there are two of said openings positioned on either side of said central portion.
 17. A biopsy device comprising: a housing having a distal end and a proximal end; an outer cannula disposed in said housing; an inner cannula slidably disposed within said outer lumen and defining an inner lumen; and at least one fluid control member disposed within said housing.
 18. A device according to claim 17, wherein said fluid control member includes at least one incision defining an opening therethrough that is normally closed.
 19. A device according to claim 18, further including two incisions that bisect each other at approximate right angles so as to form a cross-shape.
 20. A device according to claim 18, further including three incisions that intersect each other so as to form a tricuspid shape.
 21. A device according to claim 17, wherein said at least one fluid control member is positioned within said inner cannula.
 22. A device according to claim 21, wherein said inner cannula has at least one notch in which to secure said fluid control element.
 23. A device according to claim 21, wherein said inner cannula has at least one projection that secures said second fluid control element to said inner cannula member.
 24. A device according to claim 17, further including an outer cannula hub positioned adjacent to a distal end of said housing, and wherein said fluid control element is disposed within said outer cannula hub.
 25. The biopsy device of claim 17, further including a collection trap connected to a proximal end of said housing, wherein said at least one fluid control element is connected to said collection trap.
 26. The biopsy device of claim 25, wherein said at least one fluid control element is disposed within a pilot port formed in an end of said collection trap.
 27. The biopsy device of claim 26, wherein said at least one fluid control element has an elongated profile that tapers from a first diameter at a distal end to a second diameter that is smaller than said first diameter at a proximal end.
 28. The biopsy device of claim 25, wherein said collection trap includes a selectively removable cap that secures to an end of said collection trap, wherein said at least one fluid control element is positioned between said cap and said collection trap.
 29. The biopsy device of claim 28, wherein said fluid control element includes an outer ring, a central selectively deformable portion and at least one opening, wherein said central selectively deformable portion is deformable between a closed position where said at least one opening is substantially closed, and an open position, wherein said at least one opening is open so as to permit fluid to pass therethrough.
 30. The biopsy device of claim 17, wherein said housing includes an open proximal end to which a collection trap is selectively secured, wherein said at least one fluid control element is positioned within said open proximal end of said housing, said fluid control element being normally closed when said collection trap is not secured to said proximal end of said housing, and where said fluid control element is selectively deformable so as to be open and permit fluid flow therethrough when said collection trap is secured to said proximal end of said housing.
 31. The biopsy device of claim 30, wherein said fluid control element includes a flexible body member and a normally closed valve component secured thereto that has said at least one normally closed incision therein.
 32. The biopsy device of claim 31, wherein said body portion further includes a mounting flange.
 33. The biopsy device of claim 31, wherein said body portion further includes a neck member, said neck member being sized so as to be receivable within an aspiration passageway positioned within said housing.
 34. The biopsy device of claim 17, wherein said body portion further includes a selectively movable aspiration tube having an open proximal end and wherein said at least one fluid control element is positioned over said proximal end of said aspiration tube, said at least one fluid control element being normally closed so as to substantially limit fluid from passing therethrough.
 35. The biopsy device of claim 34, wherein said fluid control element includes an elongated sleeve defined by an open first end that is sized to receive said aspiration tube and a second end that is normally closed.
 36. The biopsy device of claim 35, wherein said second end includes at least one incision therein.
 37. The biopsy device of claim 17, wherein said device includes at least two fluid control elements. 